The importer of the ingredients used to make Kronic says the idea of testing workers for their use is ridiculous.
Matt Bowden, whose company imports the ingredients used to make Kronic, says cannabinoids are a legal substance.
"Testing urine to find out what good, hard-working employees have been doing in the weekend? Don't take the piss," Bowden said in a statement.
Debate is building over whether workplaces should test for legal drugs such as Kronic.
Crown research institute Environmental Science and Research spent months testing 43 synthetic cannabis products available in New Zealand and has announced it is able to identify their active ingredients.
Kirk Hardy from the New Zealand Drug Detection Agency says the way the drugs have been marketed and media hype have contributed to an escalating problem.
"We're hearing that's legal, it can't be that harmful," he told TV ONE's Breakfast.
Earlier this month two synthetic cannabis products - Kronic Pineapple Express and Juicy Puff Super Strength - were removed from shops after it was found they contained a prescription-only drug, the anti-anxiety medication phenazepam.
Hardy added the agency conducts 50,000 drug tests a year, with a 10% positive test rate.
"It's huge. It's quite scary when you consider most of the workplaces we test are to do with safety-sensitive areas. They are places where if mistakes happen people are potentially going to be seriously injured," Hardy said.
And he likened the use of legal highs in your personal time to drinking too much and turning up at work impaired.
He also referenced the warning of Kronic's inventor, American professor John Huffman, that people should stop using the drug immediately because of serious psychological problems associated with it.
"If you've got the inventor of these products saying it, I'd suggest stop."
Matthew Beattie, the chief executive of the workplace healthcare company Instep, told Breakfast the synthetic drugs are an issue for the wider workplace.
"Scientifically we're still looking at the effects of these drugs in terms of how much time after use they will affect impairment.
"Every indication from the scientists is that these products are dangerous and may even be more dangerous than cannabis itself," he said.
But Bowden said he is concerned by any move to test for the identified ingredients.
"Employers should focus on whether or not an employee is impaired at work, or a danger to themselves and others, rather than worrying about whether an employee has recently drunk alcohol or used a legal high," he said in a statement.
Bowden said employers and employees should remember that synthetic cannabinoids are a legal substance, and would not therefore automatically be covered by a Drug and Alcohol Policy.
But he added employers had every right to crack down on employees whose use of legal highs put others at risk at work, or stopped them from doing their jobs properly.
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